Moscow, Jan 10 (IANS/RIA Novosti): One of the two reactors of Romania's Cernavoda nuclear power plant was shut down automatically by the safety system for unknown reasons late Wednesday, the RL news portal reported.

"Unit Two shut down on Wednesday evening, reasons unknown," Dumitru Dina, who heads the plant operator Nuclearelectrica National Nuclear Power Corp, was quoted as saying.

Dina said the shutdown was "nothing serious" and posed no threat.

The news came about a month after Unit One of the plant briefly shut down when a storm in the area caused disruptions in electricity transmission lines in December 2012.

Cernavoda, the country's only nuclear power plant, is located about 160 km east of the capital Bucharest and accounts for about 18 percent of the country's total electricity output.

It was designed in the 1980s by Atomic Energy of Canada Limited and has two units with Canadian-made CANDU (CANada Deuterium Uranium) pressurised heavy water reactors.